1. Field of Invention
The present invention relates to a multicast group management method and a wireless network apparatus using the same, and more particularly, to a management method by using virtual access units for dividing groups.
2. Related Art
Recently, users of wireless networks are increasing day by day, such that the consumption of network bandwidth and the demand for network addresses are increasing as well. To solve the problems, the wireless network service providers and the wireless network equipment manufacturers propose a concept of multicast group through which the consumption of network bandwidth can be reduced.
Internet Group Management Protocol (IGMP) is a protocol for managing the multicast group. A node can send a host membership report message to a router, so as to create or join a multicast group in the router. When the router receives a multicast packet, such as media information, assigned to the multicast group, the multicast packet is transmitted to each node of the multicast group.
In addition, when the nodes of the multicast group, for example wireless devices, enable power saving mode for saving power or other reasons, they are entering a power save mode or standby mode. However, according to the wireless communication protocol in IEEE802.11, if a wireless device is unable to receive the media information transmitted by a router due to enabling of the power saving mode, the media information to be transmitted by the router must be saved, and until the wireless device is awake, the media information then can be transmitted to the wireless device.
Moreover, in the same multicast group, other wireless devices which disable the power saving mode or without the power saving mode have to wait until then before they can receive the media information. Therefore, it may cause a delay of receiving the media information and have an influence of fluency of receiving the media information for those wireless devices.